Molecular design exhibiting LCST-type phase separation in water has been widely accepted as desolvation of water-soluble amphiphilic polymers with a small alkyl group triggered by heat. However, for organic media, molecular design is not yet achievable due to the difficulty in designing the entropy-driven exothermic desolvation. In this report, we demonstrate LCST-type phase separations of poly(2-hydroxyethyl methacrylate) (PHEMA) and related poly(hydroxyalkyl (meth)acrylate)s in an organic medium at ambient temperature. Our design is based on the utility of a binary solvent mixture of hydrogen-bonding solvents for solvation and non-polar solvents for desolvation. The thermal cleavage of the hydrogen bond between the hydroxy group of the polymer chain and the hydrogen-bonding group of the solvent easily induced the LCST-type phase separation. We revealed a correlation between the critical molar ratio for LCST-type phase separation and the length of the alkyl groups both in the polymer side chain and 1-alcohol good solvents. These findings led to the development of a reliable molecular design strategy that could facilitate the development of smart materials in organic solvents.

中文翻译：

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PHEMA 和相关聚（甲基）丙烯酸羟烷基酯在混合有机溶剂中氢键诱导的 LCST 型相分离的热裂解


在水中表现出 LCST 型相分离的分子设计已被广泛接受为具有小烷基的水溶性两亲性聚合物通过热引发的去溶剂化。然而，对于有机介质，由于熵驱动的放热去溶剂化的设计困难，分子设计尚无法实现。在本报告中，我们展示了聚（甲基丙烯酸2-羟乙酯）（PHEMA）和相关聚（（甲基）丙烯酸羟烷基酯）在环境温度下在有机介质中的LCST型相分离。我们的设计基于用于溶剂化的氢键溶剂和用于去溶剂化的非极性溶剂的二元溶剂混合物的用途。聚合物链的羟基与溶剂的氢键基团之间的氢键热断裂很容易引起LCST型相分离。我们揭示了 LCST 型相分离的临界摩尔比与聚合物侧链和 1-醇良溶剂中烷基长度之间的相关性。这些发现导致了可靠的分子设计策略的开发，可以促进有机溶剂中智能材料的开发。